diff --git a/libsanitizer/ChangeLog b/libsanitizer/ChangeLog
index ce59f906aaf..7e206f9b96c 100644
--- a/libsanitizer/ChangeLog
+++ b/libsanitizer/ChangeLog
@@ -1,3 +1,7 @@
+2012-11-23  Kostya Serebryany  <kcc@google.com>
+        
+	* merge.sh: a script that will help merges from upstream.
+
 2012-11-23  Jakub Jelinek  <jakub@redhat.com>
 
 	* tsan/Makefile.am (AM_CXXFLAGS): Remove -Wno-variadic-macros.
diff --git a/libsanitizer/README.gcc b/libsanitizer/README.gcc
index 8fb0a932b40..92759df2eb9 100644
--- a/libsanitizer/README.gcc
+++ b/libsanitizer/README.gcc
@@ -13,3 +13,6 @@ http://llvm.org/svn/llvm-project/compiler-rt in the following directories:
 Trivial and urgent fixes (portability, build fixes, etc.) may go directly to the
 GCC tree.  All non-trivial changes, functionality improvements, etc. should go
 through the upstream tree first and then be merged back to the GCC tree.
+The merges from upstream should be done with the aid of the merge.sh script;
+it will also update the file MERGE to contain the upstream revision
+we merged with.
diff --git a/libsanitizer/merge.sh b/libsanitizer/merge.sh
new file mode 100755
index 00000000000..6918ee2475f
--- /dev/null
+++ b/libsanitizer/merge.sh
@@ -0,0 +1,79 @@
+#!/bin/bash
+
+# FIXME: do we need a license (or whatever else) header here?
+
+# This script merges libsanitizer sources from upstream.
+
+get_upstream() {
+  rm -rf upstream
+  #cp -rf orig upstream
+  svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk upstream
+}
+
+get_current_rev() {
+  cd upstream
+  svn info | grep Revision | grep -o '[0-9]*'
+}
+
+list_files() {
+  (cd $1; ls *.{cc,h} 2> /dev/null)
+
+}
+
+change_comment_headers() {
+  for f in $(list_files $1); do
+    changed=$(awk 'NR != 2 && NR != 3' < $1/$f)
+    echo "$changed" > $1/$f
+  done
+}
+
+# ARGUMENTS: upstream_path local_path
+# This function merges changes from the directory upstream_path to
+# the directory  local_path.
+merge() {
+  upstream_path=upstream/$1
+  local_path=$2
+  change_comment_headers $upstream_path
+  echo MERGE: $upstream_path
+  all=$( (list_files $upstream_path; list_files $local_path) | sort | uniq)
+  #echo $all
+  for f in $all; do
+    if  [ -f $upstream_path/$f -a -f $local_path/$f ]; then
+      echo "FOUND IN BOTH     :" $f
+      # diff -u $local_path/$f $upstream_path/$f
+      cp -v $upstream_path/$f $local_path
+    elif [ -f $upstream_path/$f ]; then
+      echo "FOUND IN UPSTREAM :" $f
+      echo "UNSUPPORTED YET" && exit 1
+    elif [ -f $local_path/$f ]; then
+      echo "FOUND IN LOCAL    :" $f
+      echo "UNSUPPORTED YET" && exit 1
+    fi
+  done
+
+}
+
+fatal() {
+  echo "$1"
+  exit 1;
+}
+
+pwd | grep 'libsanitizer$' || \
+  fatal "Run this script from libsanitizer dir"
+get_upstream
+CUR_REV=$(get_current_rev)
+echo Current upstream revision: $CUR_REV
+merge include/sanitizer include/sanitizer
+merge lib/asan asan
+merge lib/sanitizer_common sanitizer_common
+merge lib/interception interception
+
+rm -rf upstream
+
+# Update the MERGE file.
+cat << EOF > MERGE
+$CUR_REV
+
+The first line of this file holds the svn revision number of the
+last merge done from the master library sources.
+EOF